DateCalc is a calender-based program originally designed for calculating expected shipping days, based on a maximum and minimum number of business days.
Soon I realized that I had to account for holidays.
Version 1.1 now released supports U.S. Federal holidays, state holidays (including Puerto Rico),
Canadian Holidays (All Provinces),
and Bank Holidays for Great Britain.
Once you pick your location, the program remembers.
This is a trial version that will run for 15 days.
I'm also open to additions and changes - but so far I'm not including dates that require lunar calculations (first day of summer, etc) as I'm still wrapping my mind around the math
Requires Windows 2000 or later, but it might run on Win 95 or 98, I just don't bother testing those anymore!